1-Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Molecular phosphorescent heteroleptic bis-tridentate iridium(III) emitters have been prepared via (1)-arene intermediates. In the presence of 4.0mol of AgOTf, the complex [(IrCl{(3)-N,C,N-(pyC(6)HMe(2)py)})(-Cl)](2) (1; pyC(6)H(2)Me(2)py=1,3-di(2-pyridyl)-4,6-dimethylbenzene) reacted with 9-(6-phenylpyridin-2-yl)-9H-carbazole (PhpyCzH) and 2-phenoxy-6-phenylpyridine (PhpyOPh) to give [Ir{(3)-N,C,N-(pyC(6)HMe(2)py)}{(3)-C,N,C-(C(6)H(4)pyCzH)}]OTf (2) and [Ir{(3)-N,C,N-(pyC(6)HMe(2)py)}{(3)-C,N,C-(C(6)H(4)pyOPh)}]OTf (3). The X-ray diffraction structures of 2 and 3 reveal that the carbazolyl and phenoxy substituents of the C,N,C ligand coordinate to the metal center to form an (1)-arene bond. Treatment of 2 and 3 with KOtBu led to the deprotonation of the coordinated carbon atom of the (1)-arene group to afford the molecular phosphorescent [5t+4t] heteroleptic iridium(III) complexes [Ir{(3)-N,C,N-(pyC(6)HMe(2)py)}{(3)-C,N,C-(C(6)H(4)pyCz)}] (4) and [Ir{(3)-N,C,N-(pyC(6)HMe(2)py)}{(3)-C,N,C-(C(6)H(4)pyOC(6)H(4))}] (5). These complexes are green emitters that display short lifetimes and high quantum yields of 0.73 (4) and 0.87 (5) in the solid state.